The Botrychiopsis Genus and Its Biostratigraphic Implications in Southern Paraná Basin Anais Da Academia Brasileira De Ciências, Vol
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Anais da Academia Brasileira de Ciências ISSN: 0001-3765 [email protected] Academia Brasileira de Ciências Brasil Jasper, André; Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; Menegat, Rualdo The Botrychiopsis genus and its biostratigraphic implications in Southern Paraná Basin Anais da Academia Brasileira de Ciências, vol. 75, núm. 4, dezembro, 2003, pp. 513-535 Academia Brasileira de Ciências Rio de Janeiro, Brasil Available in: http://www.redalyc.org/articulo.oa?id=32775409 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Anais da Academia Brasileira de Ciências (2003) 75(4): 513-535 (Annals of the Brazilian Academy of Sciences) ISSN 0001-3765 www.scielo.br/aabc The Botrychiopsis genus and its biostratigraphic implications in Southern Paraná Basin ANDRÉ JASPER1, MARGOT GUERRA-SOMMER2, MIRIAM CAZZULO-KLEPZIG2 and RUALDO MENEGAT2 1Setor de Botânica e Paleobotânica, Museu de Ciências Naturais, Centro Universitário UNIVATES (SBP/MCN/UNIVATES),95900-000 Lajeado, RS, Brasil 2Instituto de Geociências, Universidade Federal do Rio Grande do Sul (IG/UFRGS) 91501-970 Porto Alegre, RS, Brasil Manuscript received on February 3, 2003; accepted for publication on July 23, 2003; presented by Alcides N. Sial ABSTRACT Botrychiopsis has been considered an important floristic element of Westphalian/Artinskian associations of the Paraná Basin. The occurrence of Botrychiopsis in roof-shales of the Rio Bonito Formation in Southern Paraná Basin (Quitéria area), supported by the identification of Botrychiopsis valida, enlarges the genus biochron. Consequently, the stratigraphic hierarchy for Botrychiopsis plantiana and Botrychiopsis valida was defined for the Paraná Basin. Although it is climatically controlled and related to a deglaciation icehouse stage, stratigraphic distribution of the genus presents a substantial climate tolerance, from cold/cool to warm/temperate conditions. A new phytostratigraphic zonation is proposed for the southern portion of the basin that includes the Botrychiopsis Zone (Asselian/Kungurian), which is subdivided into the Botrychiopsis plantiana (Asselian/Artinskian) and Botrychiopsis valida (Late Artinskian/Kungurian) subzones. Key words: Botrychiopsis, biostratigraphy, Paraná Basin, Permian, palaeoclimatology, Gondwana. INTRODUCTION sic – Early Cretaceous and Late Cretaceous) encom- pass continental strata and volcanic rocks. Each The intracratonic Paraná Basin covers 1.700.000 megasequence corresponds to previously proposed square kilometers of East and Central South lithostratigraphic units. America (1.100.000 square kilometers in Brazil) and The Carboniferous – Early Triassic (CET) encloses Paleozoic, Mesozoic and, locally, Ceno- megasequence represents a second-order transgres- zoic sedimentary and volcanic rocks. According to sive – regressive cycle. It contains a basal transgres- Milani et al. (1998), the Paraná Basin comprises sive unit overlain by a regressive succession. The six stratigraphic megasequences bounded by interre- basal succession includes the Itararé Group and Rio gional unconformities (sensu Vail et al. 1977). The Bonito and Palermo formations. three lower megasequences (Ordovician – Silurian, Botrychiopsis plantiana, recoverd from thick Devonian and Carboniferous – Early Triassic) con- sandstone and siltstone strata, was recorded in the sist of transgressive – regressive cycles whereas the megafloras of the lower part of the Brazilian Gond- three upper megasequences (Late Triassic, Juras- wana succession, which comprises lowland glacio- Correspondence to: André Jasper continental deposits of the Itararé Group (Millan E-mail: [email protected] An Acad Bras Cienc (2003) 75 (4) 514 ANDRÉ JASPER ET AL. 1975, 1979, Cazzulo-Klepzig and Guerra-Sommer shales in Southern Paraná Basin (Quitéria area), as 1983, Zampirolli 2001). discussed herein, allow to infer the relationship be- The synonymization of distinct taxa to this tween the biostratigraphic distribution of this genus morphogenus, which is characterized by heteromor- and its tolerance to climate changes. In this case, cli- phy, took place for more than a century (1844-1971) mate change has been associated with a deglaciation during which several Earth Science paradigms were phase of an icehouse period and is represented by an established and abandoned, from the Fixist models evolution from cool-temperate to warm-temperate to Plate Tectonics. The main studies that produced climate. The validation of this hypothesis would the current genus conception are presented in Fig. 1. then broaden the current parameters used to inter- Studies of Archangelsky and Arrondo (1971) pret the climatic conditions favorable for the devel- demonstrated the biogeographic and biostrati- opment of these plants. graphic importance of the genus in Gondwana suc- This paper comprises the first step of a larger cessions. These sequences occur in Argentina project that aims to evaluate the chronostratigraphic (Sessarego and Césari 1986, Archangelsky et al. significance of the Botrychiopsis within Gondwana. 1987, Archangelsky and Cúneo 1987, Andreis and It was carried out to verify earlier taxonomic and Archangelsky 1996); Brazil (Millan 1975, 1979, biostratigraphic descriptions of Botrychiopsis forms 1987a,b, Rösler 1978, Guerra-Sommer and Caz- of the Southern Paraná Basin. This revision was re- zulo-Klepzig 1981, Guerra-Sommer and Cazzulo- quired due to the reduced nature of previous descrip- Klepzig 1993); South Africa (Rayner 1985, 1986, tions, which did not define the diagnostic differences Rayner and Coventry 1985, Anderson and Ander- between previously identified and original material. son 1985, Kovács-Endrödy 1991), India (Srivastava 1997) and Australia (Rigby 1973, 1993, Retallack REVIEW OF THE Botrychiopsis OCCURENCE 1980). IN SOUTHERN PARANÁ BASIN The paleofloristic assemblages show a homo- Forms related to Botrychiopsis have been identified geneous composition dominated by foliar organs of in Rio Grande do Sul State in Faxinal, Base of Morro plants with arborescent habit as well as remnant Papaléo and Quitéria outcrops (Fig. 2). shrub-like plants, such as Botrychiopsis plantiana. The Faxinal outcrop, described by Morgenthal Shrub-like plants identified as Botrychiopsis et al. (1970) and later by Andreis et al. (1979), is plantiana have also been recorded in the southern- located in the northeastern portion of the Barão do most portion of the Paraná Basin, within the Glos- Triunfo topographic Sheet, close to the confluence sopteris Flora and are associated with fluvial, delta of the Grande and Faxinal creeks, about 10 km west- and estuarine sedimentary rocks at the base of the northwestward from the Mariana Pimentel District. Rio Bonito Formation (Pasqualini et al. 1986). The exposure includes variable amounts of The presence of Botrychiopsis in Paleozoic sandstone and mudstone related to the uppermost Gondwana floras of the Paraná Basin has usually part of the Itararé Group in the Rio Grande do Sul been associated with tundra and taiga environments State. It represents the westernmost exposure of a (Archangelsky 1971, 1978, 1984, Rocha-Campos paleovalley that extends from Potreiro Grande, 4 kM and Archangelsky 1985, Retallack 1980, 1999). eastwards from the Mariana Pimentel District. In their description of the Glossopteris Flora Andreis et al. (1979) recognized two infor- Early Permian evolution in Southern Brazil, Guerra- mal siltstone facies (white and grayish brown silt- Sommer et al. (1991, 2001) regarded Botrychiop- stone facies). Isolated Rubidgea-type leaves, Botry- sis plantiana as a remnant plant from a rigorous chiopsis fronds and small platispermic seeds rep- periglacial cold climate. resent most of the quantitatively poor megafloristic The first records of Botrychiopsis within roof- association. Minor amounts of the Cordaites, Glos- An Acad Bras Cienc (2003) 75 (4) Botrychiopsis AND ITS BIOSTRATIGRAPHIC IMPLICATIONS IN SOUTHERN PARANÁ BASIN 515 Taxa Quotation Author Year Botrychiopsis weissiana Kurtz 1895 Botrychiopsis weissiana Kurtz 1921 Adiantites (?) robustus Wallkom 1934 Cardiopteris cf. frondosa Wallkom 1934 (?) Botrychiopsis weissiana ? Noeggerathia sp. Wallkom 1934 (?) Botrychiopsis weissiana Kurtz & Frengüelli 1944 Gondwanidium plantianum Gerth & Frengüelli 1944 ? Adiantites sp. Frengüelli 1946 Gondwanidium plantianum Gerth & Frengüelli 1946 Botrychiopsis weissiana Archangelsky & Arrondo 1971 Odontopteris plantiana Carruthers 1869 Neuropteridium validum Feistmantel & Kurtz 1895 Neuropteridium validum Feistmantel & Seward 1903 Neuropteridium validum Feistmantel & Arber 1905 Neuropteridium plantianum White 1908 Botrychiopsis plantiana Neuropteridium plantianum Lundqvist 1919 Neuropteridium validum Feistmantel & Kurtz 1921 Neuropteridium validum Kurtz 1921 Neuropteridium plantianum Dolianiti 1953 Botrychiopsis plantiana Archangelsky & Arrondo 1971 Gondwanidium plantianum Rigby 1973 Otopteris ovata Mc’Coy 1847 Neuropteris valida Feistmantel 1876 Neuropteris valida Feistmantel 1879 Neuropteridium validum Feistmantel 1880 Botrychiopsis valida Godwanidium validum Gothan 1927 Gondwanidium validum Gothan 1941 Gondwanidium validum Gothan 1966 Botrychiopsis valida Archangelsky & Arrondo 1971 Botrychiopsis ovata Gould 1976 Botrychiopsis ovata Rettalack 1980 Fig. 1 – Current Botrychiopsis genus conception. sopteris, Gangamopteris and